The invention relates to a linear actuator comprising a linear motor, more especially in the form of a pneumatic motor, which has a housing containing an axially moving piston which is connected with an actuating rod extending out of the motor housing at a working end thereof, a control device, for instance in the form of valve means, for operation of the motor, and a sensor means responsive to certain positions of the actuating rod.
In such linear actuators the linear motor is normally in the form of a cylinder and piston unit, whose piston rod connected with the piston and extending out of the cylinder represents the actuating rod, which is able to be connected with a component to be moved or with some other load. The linear motor is placed in the position where it is to be used and the driving fluid, as for instance compressed air, is supplied and vented via pressure lines such as flexible hose. In order to control the flow of the driving fluid devices are employed, which are frequently in the form of valve devices such as electromagnetically operated ones. In order to cause automatic operation of the motor there may be a sensor device, which may comprise one or more sensors such as electrical, magnetic, pneumatic or mechanical sensors, with which certain positions of the actuating rod may be detected in order to operate the control device in accordance therewith. Linear drive actuators as so for available possess a large number of individual groups of components as for instance the linear motor, the control device and the sensor means, which are produced separately from each other and are also separately installed. The operations required for such assembly and production are slow and furthermore extensive wiring and conductor laying operations are required in order to connect the individual components with each other as a circuit. In addition to the extensive assembly operations the considerable space requirement is a disadvantage and furthermore the line connections tend to be readily damaged by moving machine parts.